Method for cooling roasted coffee



July 25 1967 H. 1.. SMITH, .JR

METHOD FOR COOLING ROASTED COFFEE 8 Sheets-Sheet 1 Filed Jan. 24, 1966HORACE L. SM/T/LJR.

July 25, 1967 H. 1.. SMITH, JR

METHOD FOR COOLING ROASTED COFFEE 8 Sheets-Sheet 2 Filed Jan. 24, 1966INVENTOR HORACE 4. SMITH, JR.

J A% ORNEYS y 1967 H. L. SMITH, JR 3,332,780

METHOD FOR COOLING ROASTED COFFEE Filed Jam 24, 1966 8 Sheets-Sheet 5INVENT OR HORACE L .SM/Th', JR.

BY )Wm 8 Sheets-Sheet 4 Q @w w 9M O H. L. SMITH, JR

METHOD FOR COOLING ROASTED COFFEE July 25, 1967 Filed Jan. 24, 1966 D 527 m mm. m f 12 5 85 M @Q 5 C 6; \H N9 m INVENTOR HORACE L.$M/TH,JR.

;%mf V 684/ A ORNEYS July 25, 1967 Filed Jan. 24, 1966 SPRAY QUANTITYGALLONS PER 750 POUNDS OF BEANS H. L. SMITH, JR 3,332,780

METHOD FOR COOLING ROASTED COFFEE 8 Sheets-Sheet 5 FINAL BEAN TO AIRTEMP. DIFF. -F

AND FINAL MOISTURE CONTENT-7o SPRAY TIME -S}ECONDS INVENTOR HORA 65 L.SM/ 771, JR.

BY MWWM 926W 77% ATP RNEYS July 25, 1967 H. L SMITH, JR ,3

METHOD FOR COOLING ROASTED COFFEE Filed Jan. 24, 1966 8 Sheets-Sheet 6.40- HHOLVUBdWEl SiHVlS wads SdOlS AVBdS SdOlS 814M018 SdWflCI 831000 INVENT OR HORACE L. SIM/TH, JR.

BY r/WWW 77M 8 Sheets-Sheet 7 H. L. SMITH. JR

METHOD FOR COOLING ROASTED COFFEE July 25, 1967 Filed Jan. 24, 1966INVENTOR HORACE L. SM/TH, JR.

WWW 7 7/ 9 5 A ORNEYS July 25, 1967 H, L. SMWHQJR 3,332,780

METHOD FOR COOLING ROASTED COFFEE Filed Jan. 24, 1966 8 Sheets-Sheet 8INVENTOR HORACE L. SMITH, JR.

BY M

A ORNEYS United States Patent 3,332,780 METHOD FOR COOLING ROASTEDCOFFEE Horace L. Smith, Jr., Richmond, Va., assignor to HuppCorporation, Cleveland, Ohio, a corporation of Virginia Filed Jan. 24,1966, Ser. No. 522,503 6 Claims. (Cl. 9968) This application is acontinuation-in-part of application No. 425,702 filed Jan. 15, 1965, byHorace L. Smith, Jr., for Apparatus and Method.

The invention disclosed herein relates to the cooling of particulatesolids and, more specifically, to novel, improved methods of coolingparticulate solids.

One particularly important application of the present invention is thecooling of roasted coffee beans. The principles of the present inventionwill, for the most part, be developed by relating them to this exemplaryapplication of the invention. It is to be understood, however, that thisinvention has far greater utility. The ensuing discussion of theinvention is therefore intended to be illustrative and not limiting withrespect to its scope, which is defined only by the appended claims.

At the end of a roast, coffee beans have a temperature throughout ofseveral hundred degrees Fahrenheit. Therefore, unless the roasted beansare cooled rapidly, the residual heat in the beans will prolong theroast even though no external heat is applied to the beans. The resultwill be a heavy roast which is undesirable because of lower yields andlower soluble solids content and because coffee brewed from the beanswill have a poor aroma and bitter taste.

In the past, arrest of the roast has typically been effected by dumpingwater on the roasted beans as they lie in the roaster or a cooler asdescribed in US. Patent No. 2,278,473 issued April 7, 1942, to Musherfor Coffee, for example. A major drawback of this method of quenchingthe roast is the lack of uniformity in the application of the water tothe beans. Consequently, the beans are not uniformly cooled and do nothave uniform characteristics; and coffee brewed from them is ofrelatively poor quality.

Another disadvantage of this method of quenching a roast is that heat isinefficiently transferred from the beans to the cooling fluid. Coolingtherefore proceeds slowly and with low efficiency.

Other methods of quenching the roast have heretofore been proposed. Forexample, US. Patents Nos. 3,122,439 and 2,857,683 suggest fluidizing theroasted coffee with a fluid which will extract heat from the beans. Thistechnique also results in nonuniform cooling because, as pointed out inapplication No. 425,702, the particles are virtually stagnant in afluidized bed; and the fluidizing fluid increases in temperature as itpasses upwardly through the bed. Consequently, the particles in thelower part of the bed will be cooled much more rapidly than those in theupper part of the bed.

A further disadvantage of the fluidized bed method of cooling is that,because the cooling fluid is utilized to fluidize the bed, this fluidmust be gaseous. Gases have comparatively poor heat transfercharacteristics. Consequently, these processes are relativelyinefficient. Further, because of their poor heat transfercharacteristics, gases employed in practical volumes are incapable ofarresting the roast with sufficient rapidity to prevent a heavy roast.

US. Patent No. 2,716,936 to Kopf suggests yet another process forcooling roasted coffee beans. In the Kopf process the beans are cooledwith a fluid which includes the volatiles evolved from the coffee beansduring the roast. As discussed in application No. 425,702 I have foundthat coffees such as Robustas, for example, can be substantiallyupgraded in quality by driving off certain "ice volatile substancesduring the roast and then removing these substances from the system sothat they are not restored to the roasted beans. This benefit iscompletely lost in the Kopf process in which these volatiles arerecirculated into contact with the roasted beans and materially lowertheir quality.

A further important disadvantage of the Kopf process is that thevolatiles Kopf utilizes as a cooling fluid exit from the roaster at atemperature of several hundred degrees Fahrenheit (Kopf speaks of atemperature of 410). To reduce the volume of volatiles necessary forcooling from such temperatures to a sufficiently low temperature thatthey could cool the roasted beans to room or a similarly low temperaturewould be impractical.

I have discovered that the disadvantages of the prior art coolingmethods described above can be avoided by employing a novel technique inwhich the roasted beans are simultaneously agitated or circulated andsprayed with an inert quenching liquid 1 until the temperature of thebeans is reduced to a temperature sufficiently low to arrest the roast.While the beans are being sprayed a fluid medium is also preferablycirculated through the beans to increase the speed of the quench byabsorbing heat from the beans. It is preferred that the fluid medium beat least partially saturated with the quenching liquid to maximize itsheat absorbing capacity. After the roast is arrested, cooling of thebeans may be continued until the desired final temperature is reached bymaintaining the circulation of the beans and continuing to contact themwith the fluid cooling medium.

Water is preferably employed as the quenching liquid because of theminimal expense involved. In addition, the use of water as the quenchingfluid makes it possible to vary the moisture content of the cooled beansso that this parameter will be at the optimum.

The advantages of the present invention can be realized to aconsiderable extent by mechanically effecting a continuous circulationof the roasted beans while they are being cooled. I have now discovered,however, that my novel cooling technique can be even more effectivelycarried out by producing the circulation of the beans by the novelfluid-solids contact technique described in my parent application. Inapplying this technique to the cooling of particulate solids, I utilizethe cooling medium to fluidize and rotate the bed of roasted beans whilethey are being sprayed to arrest the roast and during the re mainder ofthe cooling cycle. The fluid medium therefore both produces thenecessary circulation of the solids and also extracts a considerableamount of heat from them.

One advantage of this cooling technique over that disclosed in my parentapplication in which circulation of the beans -is effected mechanicallyis that there is a much more rapid circulation or turnover of the beansbeing cooled than can be produced by mechanical circulation oragitation. As a result, there is greater uniformity of contact betweenthe beans and the quenching liquid and the fluid cooling medium.Therefore, the beans are more uniformly cooled by application of theprinciples of the present invention; and the final product is moreuniform. This is extremely important because, as discussed above,uniformity of the roasted coffee is a major goal in the roasting ofcoffee.

Uniformity of cooling is further enhanced in the technique disclosedherein because, due to the rapid circulation of the beans, cooling ofall of the beans starts virtually simultaneously and with all of thebeans subjected to exactly the same conditions.

1 By inert gas, liquid, or fluid is meant one which will not adverselyaffect the quality of the beans or other solids with which it comes incontact.

Another important advantage of this invention is that, because of themore intimate contact between the beans and the fluid medium, the beanscan be cooled to a temperature more closely approaching the ambienttemperature of the fluid medium than has heretofore been possible in acooling cycle of reasonable duration.

Another important advantage of cooling coffee in accord with theprinciples of the present invention is that there is more intimatecontact of the fluid cooling medium and the quenching liquid with thebeans. This increases the transfer of heat from the beans to thequenching liquid and fluid medium and therefore reduces the timerequired to quench the roast. The improved heat transfer characteristicsalso result in increased efficiency in the cooling process.

An additional important advantage of effecting circulation of beans inthe manner just described is that there is a very low pressure dropthrough the bed of beans so that the power required to circulate thefluid medium is, relatively speaking, very low. This can result insubstantial cost savings.

A related advantage is that, with the bean surfaces moist, the masstransfer conditions are such that there is a highly efficientevaporative cooling effect.

Yet another important advantage of cooling roasted coffee in accord withthe principles of this invention results from the use of the same fluidmedium to fluidize and rotate the bed of beans being cooled and to coolthe beans. This simplifies the cooling apparatus and eliminates theenergy input required to effect circulation mechanically, reducing hecost of building, operating, and maintaining the cooling apparatus.

Still another important advantage of the present invention is that theliquid sprayed onto the beans is rapidly evaporated as long as the beantemperature is above 212 F. in the case of a water spray, for example.Such evap oration is accomplished by conversion of sensible heat in thebeans into latent heat of vaporization, which rapidly reduces the beamtemperature by extracting large amounts of sensible heat from the beans.

A further advantage of the present invention is that roasted coffeebeans cooled in accord with its principles have a much longer shelf lifethan beans with the same moisture content cooled by other methods.

Still another advantage of this invention is that beans can be roastedin accord with the principles'thereof both at atmospheric andsuperatmospheric pressure. Cooling techniques and apparatus in accordwith the present invention are also much much flexible and versatilethan those heretofore known. Other important advantages of the presentinvention, attributable primarily to the preferred method of effectingcirculation of the beans, are identical to those discussed in parentapplication No. 425,702.

From the foregoing, it will be apparent that the principles of thepresent invention are applicable to the cooling of particulate solidsgenerally and are not limited in usefulness to the cooling of roastedcoffee beans. Therefore, to the extent that other applications of thepresent invention are not expressly excluded from the appended claims,they are fully intended to be covered therein.

One important object of the present invention is accordingly theprovision of novel improved methods of cooling particulate solids, whichare particularly applicable to the cooling of roasted coffee beans andthe like, but are also applicable to the cooling of other materials.

Other important and related but more specific objects of the presentinvention include the provision of methods of cooling particulatesolids:

(1) Which are capable of more rapidly reducing the temperature of theparticulate solids than has heretofore been possible and are thereforecapable of substantially reducing the residual-heat induced changeswhich occur in heretofore known processes and apparatus.

(2) Which, when applied to the cooling of roasted coffee beans and likesolids, are capable of materially increasingly yields, the quality ofthe final product, and the soluble solids content in comparison to whatis obtainable when heretofore known cooling techniques are employed.

(3) Which are capable of more uniformly cooling the solids and thereforeproducing a more uniform product than is possible by techniquesheretofore known.

(4) Which provide a more eflicient transfer of heat from the solidsbeing cooled than is obtained in previously known processes.

(5) Which avoid contamination of the solids being cooled with substancessuch as violatiles driven off in a previous heating step which wouldadversely affect the properties of the finished product.

(6) In which circulation of the solids being cooled is first effectedand in which a quenching liquid is then distributed onto the solids torapidly decrease the solids temperature and thereby minimizeresidual-heat induced changes in the solids.

(7) In which a single fluid medium is used both to maintain a continuousrapid circulation of the solids being cooled and to cool the solids.

(8) Capable of cooling solids at lower cost than has heretofore beenpossible.

(9) Which are capable of utilizing low cost media such as water and airto cool the solids to ambient temperatures, but which can utilize otherliquids and fluid media, if desired.

(10) Which, when used for the cooling of roasted coffee beans, produce aproduct having a longer shelf life than roasted beans of similarmoisture content cooled by other methods.

(11) Can be employed to cool solids both at atmospheric andsuperatmospheric pressures.

Other objects, further advantages, and additional novel features of thepresent invention will be apparent from the appended claims and as theensuing detailed description and discussion proceeds in conjunction withthe accompanying drawing, in which:

FIGURE 1 is a section through apparatus for cooling particulate solidsin accord with the principles of the present invention;

FIGURE 2 is a fragment of FIGURE 1, to an enlarged scale, showingdetails of a flow control assembly employed in a reaction vesselincorporated in the apparatus of FIGURE 1;

FIGURE 3 is a sectional view, to an enlarged scale, of the lower end ofthe reaction vessel;

FIGURE 4 is a view similar to FIGURE 1, showing certain components inthe reaction vessel positioned to discharge cooled solids from thevessel;

FIGURE 5 is a schematic illustration of a control system for the coolingapparatus of FIGURE 1;

FIGURE 6 is a graph illustrating the effect of spraying a quenchingliquid on the solids being cooled in accord with the principles of thepresent invention;

FIGURE 7 is a reproduction of a temperature record strip chart showingthe changes in temperature which occur in the reaction vessel during thecooling cycle;

FIGURE 8 is a diagrammatic illustration of a second form of apparatusfor cooling particulate solids in accord with the principles of thepresent invention including a reaction vessel of the type illustratedin'FIGURE 1 for cooling particulate solids under pressure;

FIGURE 9 is a side view of a third form of cooling apparatus utilizingthe principles of the present invention in which circulation of thesolids being cooled is produced mechanically; and

FIGURE 10 is an end view of the cooling apparatus of FIGURE 9.

Referring now to the drawing, FIGURE 1 illustrates apparatus 18 forcooling roasted coffee beans or other particulate solids including areaction vessel 20 constructed in accord with the principles of thepresent invention. Reaction vessel 20 has a vertically elongatedcylindrical shell 22 which, in one actual embodiment of the presentinvention, is 70.5 inches in diameter and 90 inches high.

In this particular embodiment of the present invention, cooling iseffected at atmospheric pressure. Therefore, shell 22 may be fabricatedof relatively light gauge sheet metal.

The top wall 26 of shell 22 is provided with an inlet 28 through whichthe roasted coffee beans enter reaction vessel 20 from a roasting vessel30 connected to the reaction vessel by a dump conduit 32. A dump valve34 controls the flow of roasted beans from roaster 30 into reac tionvessel 20.

In the lower end of reaction vessel shell 22 is a centrally locatedaperture or dump opening 36 through which the cooled beans aredischarged into a hopper 38. The beans are removed from the hopper as bya pneumatic conveyor 40 for packaging, grinding, or other furthertreatment.

A second aperture 42, also formed in the lower portion of the reactorshell, accommodates an inlet conduit 44 for a fluid cooling medium. Thefluid thus supplied to the reaction vessel passes upwardly through thebed 46 of beans being cooled and is exhausted from the reaction vesselthrough an outlet conduit 48 extending through an aperture 50 in the topwall 26 of shell 22.

In addition to the components just described, reaction vessel 20 has adump mechanism 52 for discharging the cooled beans through dump opening36, a spray system 54 for distributing an inert liquid medium onto thebeans in the reaction vessel, and a fluid distributing and directing orflow control assembly 56, which also supports the beans while they arebeing cooled.

Flow control assembly 56 directs the fluid medium entering the reactionvessel into the bed of beans 46 in such a manner as to fluidize the bedof beans and rotate the fluidized bed by circulating the beans in pathsin which they move upwardly in the peripheral regions of the reactionvessel, inwardly toward the center of the reaction vessel in the upperpart of bed 46, downwardly in the central regions of the reactionvessel, and outwardly in the lower part of the bed as shown by arrows 57in FIG- URE 2. The circulation of the beans being cooled through thepath just described is of extreme importance inasmuch as this pattern ofcirculation provides intimate, uniform contact between the beans and thefluid medium. Even more important, this pattern of circulation ensuresintimate contact and uniform distribution of the inert liquiddistributed through spray system 54 onto the beans to arrest the roast.

Referring specifically to FIGURE 2, flow control assembly 56 includes anouter frustoconical flow plate 58 bolted or otherwise fixed to theinterior of reaction vessel shell 22 and an inner frustoconical flowplate 60 adapted to engage the lower edge of flow plate 58 to supportthe bed of solids 46. Outer flow plate 58 is constructed to direct60-70% of the fluid entering the reaction vessel through inlet conduit44 in a generally vertical direction upwardly through the bed of solids46. In the embodiment of the present invention mentioned above, outerflow plate 58 is fabricated from 0.125 inch thick 304 or 316 stainlesssteel. The upper surface of flow plate 58 is at an angle of 45 to thehorizontal. Its inner edge defines a circular opening 62 which isconcentric with the .centerline of the reaction vessel and through whichinner flow plate 60 extends.

Flow apertures 64 are drilled or otherwise formed in flow plate 58. Inthe actual reaction vessel just described,

-In the ensuing detailed description, exemplary embodiments of thepresent invention, will be described exclusively in conjunction withtheir application to the cooling of roasted coffee beans for the sake ofconvenience. Such description is intended to be illustrative and notlimiting.

there are 6,080 0.136 inch diameter apertures in the outer flow plate.The apertures are drilled at an angle of 45 to the upper surface of theflow plate so that, with the flow plate installed in reaction vessel 20,apertures 64 are vertically oriented. The apertures are arranged incircular and radial rows and are spaced so that the effective holespacing is uniform over the entire plate. That is, the holes are locatedso that the product of the radial spacing dimension and thecircumferential spacing dimension is essentially constant. In thisparticular flow plate, the product of the radial and circumferentialspacing dimensions is equivalent to 0.45 square inch for each holelocation. This provides a uniformly distributed flow through outer flowplate 58.

Inner flow plate 60 is also of frustoconical configura tion, but intypically fabricated of somewhat thinner material (0.0625 inch in theillustrated embodiment) than the outer flow plate. At predeterminedintervals, louvers 65 are punched or otherwise formed in flow plate 60,providing flow apertures 66 having a width of 0.625 inch and a depth of0.094 inch through the plate. Louvers 65 direct the treating fluidflowing upwardly in the lower part of the reaction vessel through nozzleplate apertures 66 into a downwardly and outwardly inclined path asshown by arrows 67 in FIGURE 2. In the range of approximately 30-40% ofthe treating fluid is discharged into the bed of solids being treatedthrough inner flow plate 60. To insure proper rotation of bed 46,louvers 65 are formed so that they will direct the fluid flowing throughapertures 66 at an angle of 30 or less to the upper surface of innernozzle plate 60.

In the embodiment of this invention mentioned previously, the radialdistance between adjacent rows of louvers 65 is 1% inches; and theapertures 66 in each row are evenly spaced and are approximately 1%inches apart.

Flow plates of the type described above are disclosed in greater detailin copending application No. 425,702, together with other forms of flowplates which may be used if desired instead of those described above.Reference may be made to the latter application if deemed necessary fora more complete understanding of the present invention.

Like outer plate 58, inner flow plate 60 is oriented with its uppersurface 68 at an angle of approximately 45 to the horizontal wheninstalled in reaction vessel 20. The angle the nozzle plates make withthe horizontal may be increased but should not be decreasedsubstantially below 30. This is to insure that the angle the uppersurfaces of the flow plates make with the horizontal exceeds the angleof repose of the beans or other product being treated. If it does not,the product will not slide off the nozzle plates when dump mechanism 52is operated to discharge the treated product from the reaction vessel.

For the foregoing it will be apparent that both the flow throughapertures 64 in outer flow plate 58 and the flow through apertures 66 ininner flow plate 60 have large velocity components tangential to thefluidized rotating bed. This provides rapid and complete circulation ofthe solids in the rotating bed through paths of the configurationdescribed above.

Inner nozzle plate 60 is fixed, as by welding, to the lower end of avertically extending sleeve 70 incorporated in dump mechanism 52. Theupper end of sleeve 70 is fixed, as by welding, to a shaft 72 connectedto the piston rod 74 of a hydraulic motor 76 supported from the top wall26 of reaction vessel shell 22 by a framework 78.

In addition to hte components just described, dump mechanism 52 includesa conical closure member 80 slidably mounted on shaft 72 at the lowerend thereof by journal bearings 82 and 84 (see FIGURE 3). Journalbearing 82 is fastened, as by brazing, directly to the closure member.Journal bearing 84 is attached to the closure member by a supportstructure including a circular bar 86 fastened to the closure member andradial bars 88 extending from bar 86 to the journal bearing. Closuremember 80 is adapted to engage a circular soft rubber gasket 90 fixed tothe bottom wall 92 of reaction vessel shell 22 around dump opening 36 toseal the opening.

To seat closure member 80 against gasket 90, a compression spring 34 isjournalled on the shaft, to which one end of the spring is attached.Compression spring 94 biases the closure member against gasket 90 toprovide a tight seal. To insure that closure member 80 remains properlyseated against gasket 90 during the cooling cycle, compression spring 94is selected so that the upward force it exerts against the closuremember will be greater than the downward force exerted by the gaseousmedium in the reaction vessel.

Dump mechanism 52 also includes an inverted, frustoconical guide 96 fordirecting the cooled beans into dump opening 36 when reaction vessel 20is dumped. The lower inner end of guide 96 is fastened, as by welding orbrazing, to the bottom wall 92 of the reaction vessel. At its upper end,guide 96 is supported by vertical standards 98 fastened, at their lowerends, to a reinforcing framework 100 of structural members fixed to thebottom wall of the reaction vessel.

The remaining important feature of reaction vessel 20 is spray system54, which includes two horizontally disposed circular headers 102 and104 adjacent the to wall 26 of reaction vessel shell 22. As showndiagrammatically in FIGURE 1, spray header 102 is supported from the topwall 26 of the reaction vessel by a bracket 106 formed of structuralmembers. Located at intervals of typically 45 along header 102 are spraynozzles 108. In one commercial application of the principles of thepresent invention, this gives a spacing between nozzles of approximately9 inches.

Header 102 is connected to a source of inert liquid medium, generallwater, by conduit 110. The water or other liquid flows through theconduit header 102 and out nozzles S onto the beans in reaction vesselin the form of a fine mist. As the beans in the reaction vessel arebeing continuously circulated by the gaseous medium supplied throughconduit 44 as they are sprayed, there is a uniform application of theliquid medium to the beans and intimate contact of the liquid with thebeans. This results in uniform rapid coo-ling of the beans and aconsequent quick arrest of the roast with the advantages discussedabove.

A relatively large volume of water is discharged through nozzles 108 inorder to rapidly cool the beans. As the temperature of the beansdecreases, it may be desirable to reduce the rate at which the inertliquid medium is added to the beans to insure, for example, that theyhave the proper moisture content when cooled but do not have wetsurfaces. This is accomplished by terminating the flow of liquid mediumthrough nozzles 108 at a predetermined point in the cooling cycle anddistributing the remainder of the liquid medium onto the beans throughheader 104. Header 104 is connected to the source of inert liquidthrough inlet conduit 112. Header 104 may be provided with the same typeof nozzles (not shown) as header 102; or, as an alternative, nozzles maybe drilled in the header. In either case, the nozzles are preferablyequidistantly spaced around the periphery of header 104 and are orientedto direct the liquid flowing through the header onto the bed 46 of beansbeing cooled.

In addition to effecting circulation of the beans being cooled in themanner described above, the fluid medium supplied to the reaction vesselis also employed in conjunction with the sprays just discussed to coolthe beans. To increase the heat absorbing capacity of the fluid mediuman air washer 114, connected by a conduit 116 to the inlet of the blower113 by which the fluid medium is supplied to the reaction vessel, may beemployed. Air washer 114 is of conventional construction. For thisreason and because its details are not part of the present invention, itis not considered necessary to describe it in detail herein.

In the actual embodiment of the present invention under discussion, airwasher 114 decreases the temperature of the fluid medium (in this caseair) from F. to 78 F. and increase its moisture content from 0.0166pound of water per pound of dry air to 0.0208 pound of water per poundof dry air, materially increasing its ca pacity to remove heat from thebeans being cooled.

The operation of the cooling apparatus just described can best besummarized by reference to FIGURES 1 and 5, the latter of which is asimplified schematic of the cooling apparatus control system. Referringnow to these figures, the cooling apparatus is preferably constructed sothat the various steps in the cooling cycle may be controlled manuallyor automatically. In the ensuing description of a typical cooling cycle,manual operation of the system will be assumed for the sake ofconvenience.

Manual control is provided by moving selector switches S120, S122, S124,S126, and S127 to the manual position in which contacts A are closed andcontacts B open. The switches are shown in this configuration in FIGURE5. Switch S128 is then closed, energizing relay R130. This, in a mannerdescribed in detail in parent application 425,702, opens dump valve 34and energizes the dump mechanism (not shown) in roasting vessel 30,discharging a batch of roasted beans from the latter through dumpconduit 32 into reaction vessel 20. Switch S128 is then opened,deactivating the dump mechanism and closing dump valve 34.

With the hot roasted beans (typically at a temperature of up to 400 F.)in the cooling apparatus, switch S132 is closed, energizing the motorM134 of blower 118. As described above, this causes blower 118 to supplya fluid medium to the reaction vessel to effect and maintain acirculation of the beans therein and to cool the beans.

As shown in FIGURE 5, a solenoid valve V136 in the inlet conduit tospray system header 102 is connected to the lead to blower motor M134through a conventional delay type relay R138. Accordingly, after thedelay set into relay R138 has elapsed, valve V136 is energized,permitting the inert liquid medium to flow into header 102 and throughnozzles 108 onto the circulating beans in reaction vessel 20. This delayis on the order of 40 seconds in one actual cooling system constructedin accord with the principles of this invention. The delay can be variedas desired for different applications of the invention.

In one actual and exemplary embodiment of the present invention, whichis designed to cool approximately 750 pounds of roasted coffee beans ata time, the spray is preferably maintained for a period of 20-40 secondsand the flow regulated so that at least 0.70 and preferably on the orderof 0.90 gallon of water per 100 pounds of roasted beans or more issprayed on them. The spray is then stopped by opening switch S140 tode-energize solenoid valve V136.

The roasted beans are sprayed in the manner just described to quencharrest the roast at a definite point and to control the moisture contentof the roasted beans, as mentioned previously. That the spray justdescribed is effective to rapidly terminate the roast is apparent fromFIGURE 7 which shows that, in one exemplary roast, the temperature ofthe beans being cooled was reduced from 310 F. to 180 F. inapproximately 33 seconds. At this lower temperature, the heat remainingin the beans will not cause undesired changes in their characteristics.

Quenching of the roast is extremely important since it has been foundthat a variation of 5-10 seconds in a roast having a duration of five tosix minutes or longer will affect the characteristics of the roastedbeans to such an extent that the difference in flavor of coffee brewedfrom them is readily detectable by the average coffee drinker. Becauseof the rapidity with which the beans are cooled by spraying them in themanner described above, such variations in the duration of the roast,caused in heretofore known processes by residual-heat induced changes,are avoided.

In the present invention a spray is particularly effective because thefluid medium has a very low velocity above the bed of beans or othersolids. Therefore, there is virtually no tendency for the gaseous mediumto blow the spray of liquid away from the beans as occurs in someheretofore known cooling apparatus.

As discussed previously, in the conventional process water is dumped onthe roasted beans as they lie in a quiescent mass in the bottom of theroasting vessel or a cooler. A typical African bean roasted and quenchedin this conventional manner has a yield loss of -16 percent. By roastingthe same beans in the manner described in parent application No.425,702, but without a quenching spray, this loss is reduced to 11.512percent. By adding a spray of the type described above to add moistureto the roasted beans in a uniformly applied fine mist, the loss isfurther decreased to less than 10 percent. This gives the processdisclosed herein an important economic advantage over the conventionalprocess.

There is another extremely important advantage to quenching the roastedcoffee beans in the manner just described. In conventional processes,the shelf life of the roasted product is approximately inverselyproportional to its moisture content. That is, as the moisture contentis increased, the shelf life of the roasted product is proportionatelydecreased. Unexpectedly, it has been found that coffees roasted and thencooled in accord with the present invention have a much longer shelflife than the same coffees roasted and cooled in the conventionalmanner, even though those roasted by the present process have a muchhigher moisture content.

As mentioned briefly above, in some application-s of the presentinvention it may be preferable to diminish the volume of the spray afterthe beans have been partially cooled. In such cases, the spray throughnozzles 108 is interrupted in the manner just described; and switch S142is closed to energize and thereby open a solenoid valve V144 in theinlet conduit 112 to spray system header 104. This permits the inertliquid to flow through conduit 112 into the spray header and through thenozzles of the latter onto the rapidly circulating beans in reactionvessel 20. Termination of this spray is effected by opening switch S142to de-energize and thereby close solenoid valve V144.

As discussed above and shown in FIGURE 7, the beans in reaction vesselare typically at a temperature on the order of 180 F. when thedistribution of inert liquid onto the beans is terminated. The beans arecooled from this temperature to a temperature typically on the order of80 F., i.e., room temperature, by continuing the circulation and coolingof the beans with fluid cooling medium supplied to reaction vessel 20 byblower 118. As shown by FIGURE 7, this may take on the order of 5-6minutes after the spray is terminated for a 750 pound batch of beans forwhich the time-temperature record of FIGURE 7 is typical.

Blower 118 is then stopped by opening switch S132, which de-energizesblower motor M134; and switch S146 is closed. Closing of switch S146energizes a solenoid R148,admitting an operating fluid to hydraulicmotor 76 in a conventional manner (not shown). Upon energization,hydraulic motor 76 moves dump sleeve 70 together with conical inner flowcontrol plate 60 and closure member 80 from the positions shown in FIG-URE 1 to the dump positions shown in FIGURE 4. This allows the cooledbeans in reaction vessel 20 to flow through the annular gap 150 betweeninner and outer flow plates 58 and 60 into frustoconical guide 96 andout the dump opening 36 in the bottom wall 92 of reaction vessel shell22 into hopper 38.

Switch S146 is then opened, de-energizing solenoid R148. This soactuates hydraulic motor 76 as to move dump sleeve 70 and shaft 72 inthe opposite, upward direction, engaging inner flow plate 60 with outerflow plate 58 and seating closure member against the rubber gasketaround dump opening 36. Upward movement of shaft 72 and dump sleeve 70may be terminated in any desired manner such as by the use of limitswitches (not shown), for example.

As shown in FIGURE 7, the whole sequence of events in the cooling cycleis typically completed on the order of 6 /2 minutes.

The cooling cycle can be controlled automatically as well as manually.For automatic operation, selector switches S120, S122, S124, S126, andS127 are thrown to Auto so that their A contacts are open and their Bcontacts are closed. Operation of the various cool-ing system componentsis then under the control of a timer T151 through the opening andclosing of its contacts T151-1 T151-5. The operation is identical tothat described above except that delay relay R138 is not employed in theenergization of solenoid valve V136 inasmuch as its function isperformed by timer T151. Timer T151 may be energized by closing normallyopen switch S152 although, in actual practice, it will normally beactivated by the energization of a relay (not shown) incorporated in acontrol system such as that shown and described in detail in parentapplication No. 425,702.

As mentioned previously, one of the important features of the novelcooling apparatus 18 described above is that the cooling can be closelycontrolled to thereby accurately regulate the characteristics of thecooled coffee beans. This is apparent from FIG- URE 6 which shows theeffect which the duration of the spray has on the final moisture contentof the cooled beans and on the temperature differential between theambient atmosphere and the beans being cooled when the spray is stopped.As shown by this figure, necessary adjustments in the moisture contentof the beans can be made by varying the duration of the spray. Thecurves in FIGURE 6 are for one particular system in which 750 poundbatches of coffee beans are cooled. These curves may vary for otherspecific applications of the principles of this invention.

This figure also shows that the temperature differential between theambient atmosphere and the sprayed beans can be reduced to as low as isnecessary to prevent residual-heat induced changes in the beans byvarying the duration of the spray. It will therefore be apparent thatfurther advantages of the novel cool-ing apparatus described hereinreside in its versatility and the control over the final cooled productthat it affords.

In much of the foregoing description, it has been presupposed thatcooling apparatus 18 was operated at atmospheric pressure. Coffeeroasted for brewing in the conventional manner is normally cooled atatmospheric pressure because beans roasted under supe-ratmosphericpressures do not expand or develop. Therefore, such coffees have a highbulk density in comparison to the conventionally roasted product.Consequently, coffee cooled under pressure has a lower volume/weightratio than that cooled at atmospheric pressure, which is disadvantageousin marketing the roasted coffee.

The disadvantage in cooling coffee at atmospheric pressure is thatyields are lower than are obtained by cooling under pressure. Therefore,pressure cooling is preferably employed for applications such as themanufacture of instant coffee where the higher bulk density of thepressure cooled coffee sent to the extraction columns is not a factor.

Moreover, it has now been found that both the advantages of pressurecooling and development of the beans may be obtained by cooling thebeans under pressure, slowly reducing the pressure in the cooling vesselto an intermediate pressure (as discussed in parent application No.425,702 this pressure may typically be 25-50 p.s.i.g. or as high as 250p.s.i.g.), and then quickly venting the cool-ing vessel from theintermediate to atmos- '11 pheric pressure. This process of coolingprovides yields equivalent to those obtained by conventional pressurecooling and, in addition, provides controlled development of the roastedbeans.

With the few simple modifications illustrated diagrammatically in FIGURE8, the cooling apparatus 18 de scribed above may be readily adapted forcooling roasted beans at superatmospheric pressure. Referring now to bethe latter figure, the reaction vessel 28 diagrammatically illustratedin this figure may be identical to the reaction vessel 20 describedabove except for the conventional modifications such as a thicker shellnecessary to adapt it to withstand above atmospheric pressures. Thereaction vessel is pressurized to the desired cooling pressure (which ispreferably generally equal to the roasting pressure which may be as highas on the order of 300 psi. as discussed in copending application No.425,702) by opening a valve V153 in a conduit 154 connecting cooler orreaction vessel 20 to an accumulator 156. Dump valve V157 is thenopened, permitting the roasted beans to flow from roaster or reactor 158to cooler 20 through transfer conduit 161]. Valve V157 is then closed,which isolates reactor 158 from cooler 20.

Accumulator 156 is connected through a conduit 162 to a circulationsystem 164 which includes a booster o-r circulator 16-6 and supply andreturn conduits 168 and 170 connected to cooler 20. Circulation of thecooling fluid is initiated by opening valves V174- and V176 in supplyand return conduits 168 and 170, permitting booster 166 to circulate thefluid from conduit 162 through supply conduit 168 into and upwardlythrough the beans in cooler 20. From cooler 28, the cooling fluid flowsthrough return conduit 170 to exhaust or into a heat exchanger (notshown) where it is cooled so that it may be recirculated.

At the same time that or after the flow of cooling fluid through cooler20 is initiated, a valve V178 may be opened to slowly vent cooler 20through a conduit 180 to an intermediate pressure, typically on theorder of 25- 50 p.s.i.g. When the intermediate pressure is reached, avalve 182 is opened, rapidly venting cooler 28 from the intermediate toatmospheric pressure through a conduit 184. The vent valves may beclosed when the pressure in cooler 20 reaches atmospheric to prevent airfrom enterin g the cooler, if desired.

The venting of cooling apparatus 18 in the manner described above isemployed in the roasting of colfee intended to be brewed by conventioneltechniques to develop the beans. In the roasting of beans for the manufacture of instant coffee, such venting may be omitted and the coffeecooled to its final temperature at the initial pressure.

In pressure cooling as in cooling at atmospheric pressure, water orother inert liquid is sprayed on the beans in the form of a fine mist asdescribed above to arrest the roast and to control the moisture contentof the roasted beans.

After the beans have cooled, a valve V186 in a transfer conduit 188between cooler 20 and a discharge hopper 190 is opened, and dumpmechanism 52 is activated as described above. This permits the cooledbeans to flow by gravity from cooler 28 into the discharge hopper,which, if desired, may be pressurized in the manner described incopending application No. 425,702.

Valve V186 is then closed and a valve V192 is opened to permit theroasted and cooled beans to flow from discharge hopper 190 throughconduit 194 onto a suitable conveyor (not shown).

As mentioned above, the advantages of the present invention may berealized to a considerable extent in coolers of the type illustrated inFIGURES 9 and and identified by reference character 195. In this type ofcooler the continuous circulation of the beans as they are neing cooledis effected manually. For the most part,

12 the details of cooler 195 are not critical to the practice of thepresent invention; and, moreover, coolers similar in -many respects tothat illustrated in FIGURES 9 and 10 are commercially available.Therefore, it is not believed necessary to describe the details of thiscooler herein.

Briefly, however, this apparatus includes an elongated, cylindrical,cooling vessel or reel 196 rotatably supported from a frame 197 by carwheels or rollers 198 at the ends and the center of the cooler. Theillustrated cooler 195 has a reel formed of 11 gauge, perforated,galvanized iron and is 16 feet long with an internal diameter of 60inches. Cast iron rings 280, assembled on reel 196, engage car wheels198 and prevent reel 196 from moving longitudinally relative to coolerframe 197. Reel 196 is surrounded by a sheet metal housing '202. Thedetails of housing 202 are not critical in the practice of the presentinvention and may be varied as desired.

Reel 196 is rotated at a speed of approximately 17 revolutions perminute by an electric motor M204 mounted on frame 197 and connectedthrough a belt drive 206 to a shaft 208 rotatably supported from theframework 197 of the cooler. Bevel pinions 210, fixed to shaft 288, meshwith and rotate bevel gears 212 which, as shown in FIGURE 9, drive theshaft 214 on which car wheels 198 are mounted. The car wheels engage thecast iron rings 200 at the ends and center of the reel and rotate it byfriction.

As shown in FIGURES 9 and 10, the beans to be cooled are dumped intoreel 196 through a galvanized inlet chute 216. A helical guide (notshown), extending from one end of the reel to the other and fastened tothe inside of the reel, distributes the beans from the inlet end 218 ofcooler 195 to discharge end 228 as reel 196 rotates. At the dischargeend of the cooler, the beams are discharged from reel 196 through achute 222 by a bucket type unloader (not shown).

After the roasted beans are dumped into cooler 195, they are sprayedwith a fine mist of water 3 as described previously to arrest the roastand to control the moisture content of the beans. For this purpose,cooler 195, which is otherwise of generally conventional construction,is provided with a spray system including an elongated pipe or header224 extending longitudinally through reel 196. Located at intervals oftypically 21.5 inches along header 224 are spray nozzles 226. Header 224is connected to a source of water or other liquid, the liquid flowingthrough header 224 and out nozzles 226 onto the beans in the form of afine mist. As the beans in the bed of beans in reel 196 are continuouslyagitated and circulated while the liquid is being sprayed, the foregoingsystem provides a uniform application of liquid to the beans.

In one actual cooler of this type, the spray is preferably maintainedfor a period of 81() seconds and the flow through header 224 regulatedto that at least 1.0 and preferably on the order of 1.1 gallons of waterper pounds of roasted beans or more is sprayed on them. The roastedbeans are sprayed in the manner just described to arrest the roast at adefinite point and to control the moisture content of the roasted beans,as mentioned previously.

The beans in reel 196 are also cooled by blowing air or other fluidthrough the perforated reel for approximately 3-5 minutes. For thispurpose, cooler housing 202 is provided with an air inlet 228 and asimilar air outlet (not shown) on the opposite side of the housing.Cooling air flows in inlet 228, through reel 196 and the charge of beanstherein, and out the exhaust opening.

Sodium bicarbonate 'or other alkaline materials may be added to Waterused as a quenching medium in this or any other embodiment of thepresent invention, if desired, to reduce the acidity of the roastedproduct although such treatment may normally not be required in roastingcoffee in accord with the principles of the present invention.

13 A fan or blower (not shown) is provided to eflect the flow of coolingair through the cooler. This fan may be of any desired construction.

Many modifications may be made in the illustrated embodiments of thepresent invention in addition to those discussed above. To the extentthat such modifications are not expressly excluded from the appendedclaims, they are fully intended to be covered therein.

As discussed above and from the foregoing description of exemplaryapplications of the present invention, it will also be readily apparentto those skilled in the arts to which the present invention pertainsthat its principles and the illustrated apparatus can be used to coolparticulate solids other than coffee beans. All such applications of thepresent invention and processes employing its principles are alsointended to be covered by the appended claims unless expressly excludedtherefrom.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. The process of cooling coffee beans and similar particulate solids,comprising the steps of:

(a) first effecting a continuous movement of the solids to be cooledwith a fluid at a temperature lower than that of the solids by effectinga flow of the fluid medium through a bed of said solids, a first part ofthe fluid medium being directed upwardly through the outer regions ofthe bed, said upwardly directed part of the fluid medium having asufliciently large vertical component to transport the particlesupwardly in the outer regions of the 'bed, and the remainder of thefluid medium being directed into the lower inner part of the bed andtoward the periphery thereof, said peripherally directed part of thefluid medium having a sufliciently high lateral flow component to causeoutward movement of the particles in the lower part of the bed; andthen,

(b) while maintaining said circulation, distributing an inert liquidmedium onto said solids to rapidly reduce the temperature of said solidsand thereby rninimize residual-heat induced changes therein.

2. The process of cooling coffee beans and similar particulate solids,comprising the steps of:

(a) pressurizing the environment in which said solids are located;

('b) effecting .a continuous movement of the solids to be cooled with afluid at a temperature lower than that of the solids by elfecting a flowof the fluid medium through a bed of said solids, a first part of thefluid medium being directed upwardly through the outer regions of thebed, said upwardly directed part of the fluid medium having asufliciently large vertical component to transport the particlesupwardly in the outer regions of the bed, and the remainder of the fluidmedium being directed into the lower inner part of the bed and towardthe periphery thereof, said peripherally directed part of the fluidmedium having a sufliciently high lateral flow component to causeoutward movement of the particles in the lower part of the bed;

(0) while maintaining said circulation, distributing an inert liquidmedium onto said solids to rapidly reduce the temperature of said solidsand thereby minimize residual-heat induced changes therein;

(d) slowly reducing the pressure on the solids being cooled to anintermediate pressure above atmospheric pressure while they are beingcooled; and then (e) quickly reducing the pressure on said solids fromsaid intermediate presssure to atmospheric pressure to effect acontrolled developmentof said solids.

3. The process of cooling coflee beans and similar partciulate solidswith a fluid at a temperature lower than that of the solids by effectinga flow of the fluid medium through a bed of said solids, a first part ofthe fluid medium being directed upwardly through the outer regions ofthe bed, said upwardly directed part of the fluid medium having asufficiently large vertical component to transport he particles upwardlyin the outer regions of the bed, and the remainder of the fluid mediumbeing directed into the lower inner part of the bed and toward theperiphery thereof, said peripherally directed part of the fluid mediumhaving a sufliciently high lateral flow component to cause outwardmovement of the particles in the lower part of the bed.

4. The process of claim 1 wherein the flow of said fluid medium iscontinued after the distribution of the inert liquid medium onto thesolids has been completed to further reduce the temperature of saidsolids.

5. The process of claim 1, together with the step of increasing therelative humidity of said fluid medium before it is passed through saidsolids to thereby augment its heat absorbing capabilities.

6. The process of claim 1, together with the step of maintaining thesolids under a superatmospheric pressure while they are cooled.

References Cited UNITED STATES PATENTS 255,477 3/ 1882 Ullrich 3420 X741,831 10/1903 Provost 34-174 X 1,237,931 8/ 1917 Malvezin 99-681,547,655 7/1925 Johnston 99-68 2,099,945 11/ 1937 Simpson 99-682,105,778 1/1938 Behr et a1 34-34 2,309,036 1/ 1943 Beardsley 62-572,400,051 5/ 1946 Pasquier 34-37 X 2,607,199 8/ -2 Christensen 62-572,716,936 9/ 1955 Kopf 99-68 3,097,828 7/1963 Grun 222-195 3,169,3802/1965 Callow et a1. 62-57 A. LOUIS MONACELL, Primary Examiner.

M. W. GREENSTEIN, Assistant Examiner.

1. THE PROCESS OF COOLING COFFEE BEANS AND SIMILAR PARTICULATE SOLIDS,COMPRISING TH STEPS OF: (A) FIRST EFFECTING A CONTINUOUS MOVEMENT OF THESOLIDS TO BE COOLED WITH A FLUID AT A TEMPERATURE LOWER THAN THAT OF THESOLIDS BY EFFECTING A FLOW OF THE FLUID MEDIUM THROUGH A BED OF SAIDSOLIDS, A FIRST PART OF THE FLUID MEDIUM BEING DIRECTED UPWARDLY THROUGHTHE OUTER REGIONS OF THE BED, SAID UPWARDLY DIRECTED PART OF THE FLUIDMEDIUM HAVING A SUFFICIENTLY LARGE VERTICAL COMPONENT TO TRANSPORT THEPARTICLES UPWARDLY IN THE OUTER REGIONS OF THE BED, AND THE REMAINDER OFTHE FLUID MEDIUM BEING DIRECTED INTO THE LOWER INNER PART OF THE BED ANDTOWARD THE PERIPHERY THEREOF, SAID PERIPHERALLY DIRECTED PART OF THEFLUID MEDIUM HAVING A SUFFICIENTLY HIGH LATERAL FLOW COMPONENT TO CAUSEOUTWARD MOVEMENT OF THE PARTICLES IN THE LOWER PART OF THE BED; ANDTHEN, (B) WHILE MAINTAINING SAID CIRCULATION, DISTRIBUTING AN INERTLIQUID MEDIUM ONTO SAID SOLIDS TO RAPIDLY REDUCE THE TEMPERATURE OF SAIDSOLIDS AND THEREBY MINIMIZE RESIDUAL-HEAT INDUCED CHANGES THEREIN.